Method for registering printing plates



March 25, 1941. J 0 5s ETAL 2,236,000

METHOD FOR REGISTERING PRINTING PLATES Filed Sept. 7, 1938 2Sheets-Sheet 1 r rw eiw a W mm W 0 &KL M Awm n um m n JJVM BY QW/MMSEYSMarch 25, 1941.

METHOD FOR REGISTERING PRINTING PLATES J. A. KOESSLER ETAL 2236.000

Filed Sept. 7, 1938 2 Sheets-Sheet 2 John A. oessler Kenneth 11.1%essiei INVENTORS g John W 685181 AT ORNEYS Patented Mar. 25, 1941 PATENTOFFICE METHOD FOR REGISTERING PRINTING X PLATES John A. Koesslcr, JohnW. Koessler, and Kenneth L. Kocssler, Buffalo, N. Y.

Application September 7, 1938, Serial No. 228,814

'1 Claims.

This invention relates to a method for securing registry of relatedprinting plates or forms and for facilitating the location of themake-ready upon the impression cylinder or impression plate of aprinting press. I

In making a number of superposed or related printing impressions, as inmulti-color printing, considerable difficulty is encountered in locatingthe several printing plates, blocks, forms, cuts, or the like, in suchposition that the several impressions will be in accurate superpositionor 'alinement, in other words, in registry. This is true whether theimpressions are made consecutively in the same press and with the sameimpression cylinder or plate; whether they are made with differentpresses; or whether they are made in a multi-color printing press havingplural printing stations or positions for the several impressions.

While the principles of our invention may be employed in any of theforegoing processes, we

shall discuss it here, for the purpose of delineat ing a single completeembodiment, in connection with a rotary multi color press of the typecommonly in use in newspaper printing.

In presses of this type a continuous web of paper passes through thepress from the feed roll to the cutting and folding instrumentalitiesand in its course passes between a number of pairs of rollers. Each ofthese pairs of rollers consists of a plate cylinder carrying one or morearcuate printing plates, usually cast, and an impression cylinder forpressing the moving web of paper against the type surface of the plateson the plate cylinder. The impression cylinder customarily carries onits surface a make-ready for insuring uniform contact of the web withall parts of the type surface.

For convenience we shall discuss our invention in connection withprinting in four colors. This number may be varied and is chosen onlybecause it is commonly used inthe printing of comic supplements fornewspapers.

In a rotary press for such printing there are,

' in addition to the usual feed rolls, tension rollers,

ink fountain and distributing rolls, etc., four pairs of impression andplate cylinders. In a conventional multi-color press of this type thefour plate cylinders are identical in dimension and construction andeach plate cylinder usually has a raised central ring and a plurality ofmembers called head bars which extend along the surface of the cylinderfrom the center ring to the outer edge and parallel to the axis .of thecylinder.

The curved stereotype plates are customarily plate with respect to thetype matter thereon.

clamped against the center ring with a circumfer'entially extending edgeof the plate in abutment with the center ring and with one axiallyextending edge of each plate against one of the head bars and since therelative location and sizes of the center rings and head bars on theseveral plate cylinders are identical accurate registry of the severalcolor plates is effected, according to the present invention, bytreating the stereotype plates in such manner that the edges of theplates which engage the center rings and the head bars are uniformlylocated with respect to the type surfaces throughout the series of colorplates. This treatment of the plates is effected prior to setting up theprinting press and in such manner that no testing or registering of theplates subsequent to their initial placement in the press is necessary.

It is to be understood, of course, that the several impression and platecylinders are arranged to rotate in accurately timed relation wherebywhen registry of the several impressions is once effected by properlocation of the printing plates such registry will be effectivelymaintained during the period of operation of the press.

One important advantage of our invention is the fact that registry ofsets of multi-color plates may be effected while other jobs are beingrun on the large newspaper printing presses and without interfering withtheir production during such time as is consumed in registering theplates.

The apparatus and method of our invention is further adapted to theproduction of a makeready for each impression cylinder of the presswhich may be more accurately positioned with respect to the type surfacethan has heretofore been possible and, further, a make-ready which maybe positively and directly located and ap plied to the impressioncylinder without preliminary testing and shifting to determine theproper location of the make-ready. This latter object is accomplished asan accompaniment of our new method of registering the plates and ingeneral by producing make-readys bearing locating marks which may bealined with similar permanently provided marks on the tympan or otherrelatively fixed backing for the make-ready found on each impressioncylinder. In providing for the accomplishment of the foregoing objectsWe utilize a novel proof press wherein means are provided forautomatically and graphically indicating on each proof that is pulledthe exact relationship and spacing of the center ring contacting edgeand the head bar contacting edge of the printing An exemplary embodimentof the novel instrumentalities employed in the accomplishment of ourinvention will be found illustrated in the drawings and described inthis specification but it is to be understood that the scope of ourinvention is not limited thereto or in any other way excepting asdefined in the appended claims In the accompanying drawings:

Fig. 1 is a fragmentary plan view of the impression and plate cylindersof our novel proof press;

Fig. 2 is an end elevational view thereof in cross section;

Fig. 3 is a fragmentary perspective view of a central portion of theplate cylinder of the proof press showing the intersection of the centerring and a head bar;

Fig. 4 is a fragmentary perspective view of the impression cylinder ofthe proof press showing a portion of a printed proof sheet in position;

Fig. 5 is a plan view of a tracing table with a pair of superposedproofs of related printing plates;

Fig. 6 is a fragmentary plan view of a printing station of aconventional multi-color newspaper press showing a related platecylinder and impression cylinder; and

Fig. 7 is a schematic plan view of a make-ready prepared according toour invention.

We shall now describe one specific application of the principles of ourinvention and in so doing reference will be had to rotary multi-colorpresses of the newspaper printing type employing curved stereotypeprinting plates. It is to be understood, however, that the followingdetailed description is merely by way of example and that our inventionis not to be considered as limited in any way save by the appendedclaims.

In the production of curved plates for news paper printing a matrix isproduced by impressing the type form against a flong composed of laminations of paper and the matrix so formed is then dried and placed in amolding machine where it is caused to assume a curve corresponding withthe curve of the plate cylinder of the press in which the plate is to beemployed.

Type metal is then poured into the machine: and a curved stereotypeplate is produced. The back of the plate, that is the convex surfacethereof, is then shaved or surfaced by conventional means so that theplate will be of uniform thickness.

The steps thus far discussed are conventional and well known innewspaper printing and in following the process of the present inventionno departure therefrom is noted.

In carrying out our present invention we provide and utilize anovelproof press for producing preliminary impressions or proofs of theseveral plates. As illustrated in the drawings, the proof press isprovided with a plate cylinder l and a cooperating impression cylinderl'l, these cylinders being arranged to rotate in timed relation witheach other in any convenient manner. A suitable inking roller 42 andother conventional ink fountain and distributing means (not shown) areprovided.

In the construction of our proof press it is intended to reproduce, asto certain features, the conditions which exist in the impression andplate cylinder construction of the conventional multi-color newspaperprinting machine of which the proof press is an adjunct.

In a newspaper printing machine of the type here under consideration andgenerally used there are provided on the plate cylinders center ringsand head bars against which the stereotype plates are adapted to beclamped. In practice the center ring encircles the plate cylinder midwaybetween its ends and projects above the surface of the cylinder adistance less than type height so as not to interfere with the printingof the plate. The head bars, of which there are usually several spacedabout the cylinder, project above the surface of the cylinder about thesame amount as the center ring and extend from the center ring in eachdirection parallel to the axis of the cylinder and to a point adjacentthe edge of the cylinder. The center ring and a head bar are indicatedat 30 and. 3|, respectively, in Fig. 6, where an impression cylinder anda plate cylinder of a multi-color newspaper printing press aredesignated 32 and 33, respectively.

The curved stereotype plates are placed in the nawspaper printing presswith one arcuate edge abutting the center ring and one axially extendingedge against a head bar. Clamps 34 are then applied to the other arcuateedge of the plate at the end of the cylinder to retain the plate inposition.

In constructing the plate cylinder of our improved proof press we use acylinder having the same diameter as the cylinder in the newspaperprinting press and having its center ring and head bars located as theyare located in a newspaper printing press and of the same Width. Thecenter ring and head bars of our proof press are designated l3 and 14,respectively, in the drawings. Instead of keeping the height of thecenter ring and the head bar low enough to avoid interference withprinting, as has heretofore been the practice, we construct the centerring l3 and the head bars M of our proof press so that they are exactlytype high, in order that proofs produced on the press will have printedthereon a reproduction of the center ring and head bars for indicatingtheir location with respect to the type matter. To render this printedindication more useful we preferably provide a narrow annular centralgroove l in the printing surface of the center ring and a narrowlongitudinal central groove 16 in the printing surface of each head barwhereby the otherwise solid black impressions of the center ring andhead bar will appear with a narrow white line extending centrallythereof.

Clamps I! are provided at the edge of the plate cylinder of the proofpress for retaining the stereotype plates against the center ring andhead bars in the same manner as in the newspaper printing press.

In the drawings the impression cylinder II is shown bearing a proofsheet I8 which may be held in place on the impression cylinder in anyconvenient manner. In Fig. 2 will be found a bar 19 hinged at 20 andhaving prongs on pins 21 which pierce and thereby hold one edge of theproof sheet l8. The opposite edge of the proof sheet is inserted in alongitudinal slot in a rotatable bar 2. After insertion of the edge ofthe proof sheet 13 the bar 22 is rotated to wind up any slack in theproof sheet and hold it taut on the impression cylinder. Thisconstruction is the same as that conventionally employed on theimpression cylinder of the newspaper printing press for holding themake-ready and other sheets underlying the web of news print. It isnoted that newspaper printing presses act upon a continuous Web in whichno means on the impression cylinder for holding the web itself theretoare needed.

In pursuing the method involvedin our invention, in the embodiment nowbeing described, a complete set of stereotype plates, comprising oneplate for each color to be printed in superposition, is brought to theproof press after the casting and back shaving steps previously referredto. Since the plate for printing the black matter is usually mostcomplete and generally prints borders, outlines, etc., this plate may beconveniently used as a master plate. For greater convenience this masterplate is usually placed in a conventional stereotype plate edge trimmerand one curved edge and one straight edge thereof, these being the edgesintended to contact the center ring and head bar when the plate ispositioned either in the proof press or the newspaper printing press,are trimmed straight and to such size that these edges will be closer toany given point in the type matter than the corresponding edges of theremaining plates in the set. Each plate is then successively positionedin the proof press and one or several proofs thereof are made.

The proofs are then preferably brought to a conventional tracing tablehaving a glass top and a light therebeneath and the black proof, that ofthe master plate, is placed on the table.

Referring to Fig. 5, the numeral 40 designates the tracing tablementioned above and shown there in plan view. A proof sheet 4| from theplate for printing in black, heretofore designated the master plate, isplaced upon the table and it may be secured by thumb-tacks or paste. Aproof sheet til from another plate in the set, for printing anothercolor, is then placed upon the master proof sheet All and is adjusteduntil the pictures or reading matter on the two proof sheets are inaccurate registry. At 43 in Fig. 5 a portion of the upper proof sheet 42has been broken away tomore clearly illustrate this condition.

Owing to the preliminary trimming of the edges of the black plate thisplate will be smaller than the other plates in the set and the blacklines printed by the center ring and the head bar on the proof sheetswill be closer to the matter printed by the stereotypeiplate than in theremaining plates in the set. In effect, the dges of the black lineswhich lie closest to the printed matter on the proof demarcate thoseedges of the plate which lie against the center ring and head bar duringthe printing of the proof.

As seen in Fig. 5, the border line 44 impressed upon the black proofsheet 4| by one of the head bars M of the proof press, together with itsnarrower white central guide line, is offset toward the text of theplate relative to the corresponding border line 46 ,on the superposedproof sheet 42. The distance between corresponding parts of these lines,as for instance the distance between the white central guide lines onthe two sheets, indicates the amount that the edge of the plate used inproducing the upper proof sheet 42 should be trimmed to bring the type.matter of the two plates into accurate registry in the direction of thecircumference of the plate cylinders wherein both plates are mounted onthe same plate cyl-.

inder and run consecutively or when they are mounted on plate cylindersof duplicate size and proportion and having identically located centerrings and head bars.

A similarcondition exists in Fig. 5 with respect to the vertical centralguide lines 41 and 48 of the lower and upper proof sheets 4| and 42,respectively, and the distance between the central white lines of theseguide lines indicates the amount that'the curved edge of the plate usedin producing the upper proof sheet 42 must be trimmed in order to bringthe type matter of the two plates in accurate registry in the directionof the axis of the plate cylinder when they are mounted and used asoutlined in the preceding paragraph. Proofs of the other plates in theset are then successively placed upon the black proof 4| with thesubject matter of the plates in registry and refer-- once is had to theguide lines printed upon each of the two proof sheets and the processdescribed in the case of the proof sheet 42 is repeated until the headbar and center ring contacting edges of all of the plates in the setbear a uniformly identical relation to the type matter of the plates.

Since the center ring arid head bar-contacting edges of the plate forprinting in black have previously been trimmed, the guide lines on theproof being compared therewith will in all cases be farther from theprinted context than they are on the black proof and the distancebetween corresponding lines on the black proof and the proof beingcompared therewith indicate exactly the amount which the correspondingedge of the plate being compared should be trimmed to causethe printedguide lines to exactly register when the printed context of the twoproofs are also in registry.

It should be noted that in printing each of the complete proof sheets 4|and 42 two plates are employed, one on each side of the center ring. Wehave described the method of registering the plates which print thematter appearing to the left of the central guide lines 41 and 48 inFig. 5. After this has been done the upper sheet 42 must be shifteduntil the matter to the right of these lines is in registry and the samprocess is then followed for the set of plates that prints the matter tothe right of the central guide lines 41 and 4B of Fig. 5. While a plateedge trimmer is conveniently used in our new method, its general use fortrimming the edges of stereotype plates is well-known and conventionaland no separate disclosure thereof is believed necessary.

After the edges of the several plates in a par ticular set have beentrimmed, as indicated by comparison of the guide lines impressed by thecenter line and head bars of the proof press, new proofs may be made asa check but this step is not essential to successful operation of theplate registry part of our new process.

With the plates thus provided with accurate locating edges and since theposition they assume on the several plate cylinders of the newspaperprinting press are the same throughout the set and the same as in theproof press, it is merely necessary to lock the several plates inposition with the assurance that the resultant printed matter will be inaccurate register.

It has been customary in the past, in setting up presses of the typehere being discussed, to prepare the make-ready for the impressioncylinder after the plates have been set up in the press. Thisnecessitates keeping a large press out of production for a considerableperiod of time and, of course, results in substantial waste. By ourinvention a make-ready is prepared while the stereotype plate is set upin the proof press and on a proof sheet having the previously describedprinted guide lines showing the location of the plate cylinder centerring and head bars with relation to the type matter. The proof sheet forthis purpose should be one that is made after the edge trimmingoperation previously referred to so that the proof sheet shows, bymeansof the guide lines, the location which the plate will assume whenit is set up in the newspaper printing press.

Such a make-ready is more or less diagrammatically shown in Fig. 7 whenthe numeral 50 designates a proof sheet bearing head bar and center ringimpressions, designated 5| and 52, respectively. The procedure inpreparing the make-ready, save for the presence of the lines 58 and 52,is the same as has heretofore been followed. A backing for the proofsheet 50 may be employed, if desired, and the overlays indicated at 53are applied in the conventional manner.

Fig. 6 shows guide lines which are scored or otherwise applied to'thetympan 35 or other permanent backing member of the impression cylinder32 in the printing press proper. These lines comprise preferably twoaxially extending lines at the ends of the cylinder marked 36 and a pairof crossed lines at the center of the cylinder 31, with one of the crosslines 31 in line with the lines 36 at the ends of the cylinder. Thelines 38 and 31 are so located on the tympan that the make-ready may besimply located on the impression cylinder by merely registering thelines 36 with the ends of the guide lines 5! produced by the head bar I4and alining the crossed lines 31 with the crossed guide lines appearingon the proof sheet at the juncture of the lines 5! and 52. In thismanner accurate positioning of the make-ready for each stereotype plateis effected directly without any preliminary shifting or testing.

One important advantage of our invention is the fact that registry ofsets of multi-color plates may be effected while other jobs are beingrun on the large newspaper printing presses and without interfering withtheir production during such time as is consumed in registering theplates.

In an alternative form of the method of our invention we dispense withthe tracing table heretofore referred to insofar as registering theseveral plates is concerned. In this modified procedure we provide atransparent expanse, preferably of a flexible nature, and a sheet ofCellophane has been found to serve satisfactorily.

In proceeding in accordance with this alternative the novel proof presshereinbefore described and illustrated in the drawings may be employedbut for present purposes the center ring and head bar need not be typehigh. The first step in the alternative method is, as in the principalembodiment, to trim two adjacent edges of one of the stereotype plates,usually the black plate, so that when comparisons of other plates in theset are made with the black plate the trimming necessary to cause theplates to register will always be of the other plates and not of theblack plate.

After trimming, the black plate is positioned in the proof press and aproof is struck therefrom and the proof is left in position on theimpression cylinder of the proof press. The transparent sheet, as ofCellophane, is then secured to the impression cylinder so that it coversthe proof sheet struck from the black plate and the black plate isremoved from the press and another plate of the set is positioned uponthe plate cylinder with two of its edges in contact with the stationarylocating means of the proof press.

A proof of this second plate is then impressed upon the transparentsheet and the visual effect of the two superposed impressions, owing tothe transparency of the second sheet, is substantially the same as ifboth impressions were struck onto one sheet. The discrepancy of thelocating edges of the second plate with relation to the black plate isthen checked by comparing related type matter on the two plates and thetwo adjacent locating edges of the second plate are trimmed to correctthis discrepancy.

The first proof impression from the second plate having served itspurpose, the smooth transparent sheet is wiped off with a cloth or thelike and the trimmed second plate is repositioned in the press and asecond proof is struck therefrom onto the transparent sheet to check thetrimming and the resultant registry. If further correction is requiredthe foregoing process is repeated but that is usually unnecessary.

With the original proof sheet of the black plate still in position andwith the transparent superposed sheet again wiped clean, or ifnecessary, replaced, the third plate of the set is p0si tioned in theproof press and the method employed in registering the second plate isrepeated with the third plate.

Each plate of the set is so treated and the net result, as in the firstdescribed embodiment of the instant invention, is that each plate of aset has its locating edges accurately trimmed prior to introduction ofthe plates into the actual printing press, as distinguished from theproof press, before introduction of any of the plates into the printingpress and complete registry of the set of plates is effected with nochecking or trimming after the plates are first placed in position inthe printing press.

It is desirable to use the novel proof press of Figs. 1 through 4 of thedrawings even in the last described modification of the invention inorder that make-ready sheets having the novel locating guide lines maybe produced for accurately positioning make-readies on the impressioncylinders of the multicolor printing presses.

What is claimed is:

1. The method of registering sets of stereotype printing plates for usein rotary multicolor printing presses which comprises consecutivelyimpressing proofs of the several plates in a set and simultaneouslyimpressing upon each proof sheet impressions of the plate holding andlocating bars of said proof press for graphically recording on saidproof sheet the relative position of the edges of said plates withrespect to their type matter, superposing said proof sheets with thetype matter impressed by the several stereotypeprinting plates inregistry, comparing the impressions of the plate holding means on theseveral proof sheets and measuring variations in location thereof, andsubsequently trimming the edges of the several plates to compensate forsuch variations.

2 The method of registering sets of stereotype printing plates for usein rotary multicolor printing presses which comprises consecutivelyimpressing proofs of the several plates in a set and simultaneouslyimpressing upon each proof sheet guide lines demarcating the location oftwo edges of each plate to indicate graphically the relative dispositionof such edges with respect to the type matter of the plate, superposingthe several proof sheets so produced with their type matter of theseveral proofs in registry and determining the variations in alinementbetween the guide lines demarcatlng the location of the said two edgesof each plate and subsequently trimming the plates whose said two edgesare at greater distances from corresponding points on the type matter tocause the said two edges of each plate to bear the same relationship tothe type matter of each plate in the set.

3. The method of registering a set of related stereotype printing platesfor multicolor rotary printing which comprises positioning one of theplates of said set in a proof press and strikinga proof therefrom and,without removing said proof from the proof press, positioning thereovera transparent sheet, replacing said first Plate W h another plate on theset and imp s n id transparent sheet an impre s of the Seco d plate andcomparing the superposed imDIBSSiOIIS to determine the disc p n y n stryof th two impressions, and trimming the edges of the second plate anamount sufficient to compensate for such discr p c e 4, h method ofregistering a set of related stereotype printing plates for multicolorrotary printing which comprises positioning one of the plates of saidset in a proof press and striking a pIOOf therefrom and, withoutremoving said proof from the proof press, positioning thereover atransparent sheet, replacing said first plate with another plate of theset and impressing on said transparent sheet an impression of the secondplate and comparing the superposed impressions to determine thediscrepancy in registry of the two impressions, trimming the edges ofthe second plate an amount sufficient to compensate for suchdiscrepancies, and removing the impression from the transparent sheet bywiping or the like preparatory to making further checking impressionsthereon.

5. The method of registering a set of related stereotype printing,plates for multicolor rotary printing which comprises positioning one ofthe plates of said set in a proof press and striking a proof therefromupon a proof sheet, replacing said first plate with another plate of theset and impressing an impression of the second plate on another proofsheet, comparing the two impressions with the two proof sheetssuperposed in accordance with the relative positions of the locatingedges of their respective plates to determine the discrepancy inregistry of the two impressions; and trimming the edges of one of theplates an amount sufficient to compensate for such discrepancy.

6. The method of registering sets of stereotype printing plates for usein rotary multicolor printing presses which comprises consecutivelyimpressing proofs of the several plates in a set, superposing a pair ofproof sheets, providing means for maintaining said proof sheets in thesame relative position with respect to the impressions thereon as theplates from which they are struck, providing transparent means forsimultaneously inspecting both superposed proof sheets to observe lackof registry, and trimming the edges of one of the plates to compensatefor such lack of registry.

7. The method of registering sets of stereotype printing plates for usein rotary multicolor printing presses which comprises impressing a proofof one of the plates in a set, impressing a proof from another of theplates in said set, superposing said proofs, and providing means formaintaining said proof sheets in the same relative position with respectto the impressions thereon as the plates from which they are struck,providing transparent means for simultaneously inspecting 7 bothsuperposed proof sheets to observe lack of registry, and trimming theedges of said other plate to compensate for such lack of registry.

JOHN A. KOESSLER. JOHN W. KOESSLER. KENNETH L. KOESSLER.

